org.apache.curator.framework.recipes.leader.LeaderSelector Java Examples

@Override
public synchronized void stop() {
    stopped = true;

    for (final Map.Entry<String, LeaderRole> entry : leaderRoles.entrySet()) {
        final LeaderRole role = entry.getValue();
        final LeaderSelector selector = role.getLeaderSelector();

        try {
            selector.close();
        } catch (final Exception e) {
            logger.warn("Failed to close Leader Selector for {}", entry.getKey(), e);
        }
    }

    leaderRoles.clear();

    if (curatorClient != null) {
        curatorClient.close();
        curatorClient = null;
    }

    logger.info("{} stopped and closed", this);
}
 

@Override
public synchronized void unregister(final String roleName) {
    registeredRoles.remove(roleName);

    final LeaderRole leaderRole = leaderRoles.remove(roleName);
    if (leaderRole == null) {
        logger.info("Cannot unregister Leader Election Role '{}' becuase that role is not registered", roleName);
        return;
    }

    final LeaderSelector leaderSelector = leaderRole.getLeaderSelector();
    if (leaderSelector == null) {
        logger.info("Cannot unregister Leader Election Role '{}' becuase that role is not registered", roleName);
        return;
    }

    leaderSelector.close();
    logger.info("This node is no longer registered to be elected as the Leader for Role '{}'", roleName);
}
 

public SchedulerSelector(WorkflowManagerImpl workflowManager, QueueFactory queueFactory, AutoCleanerHolder autoCleanerHolder)
{
    this.workflowManager = workflowManager;
    this.queueFactory = queueFactory;
    this.autoCleanerHolder = autoCleanerHolder;

    LeaderSelectorListener listener = new LeaderSelectorListenerAdapter()
    {
        @Override
        public void takeLeadership(CuratorFramework client) throws Exception
        {
            SchedulerSelector.this.takeLeadership();
        }
    };
    leaderSelector = new LeaderSelector(workflowManager.getCurator(), ZooKeeperConstants.getSchedulerLeaderPath(), listener);
    leaderSelector.autoRequeue();
}
 

/**
 * Start the registration of the {@link #candidate} for leader election.
 */
@Override
public synchronized void start() {
	if (!this.running) {
		if (this.client.getState() != CuratorFrameworkState.STARTED) {
			// we want to do curator start here because it needs to
			// be started before leader selector and it gets a little
			// complicated to control ordering via beans so that
			// curator is fully started.
			this.client.start();
		}
		this.leaderSelector = new LeaderSelector(this.client, buildLeaderPath(), new LeaderListener());
		this.leaderSelector.setId(this.candidate.getId());
		this.leaderSelector.autoRequeue();
		this.leaderSelector.start();

		this.running = true;
	}
}
 

/**
 * 启动主节点选举
 */
public static void start() {
    synchronized (lock) {
        if (singleton != null) return;
        ZkLeaderElection leaderElection = new ZkLeaderElection();
        LeaderSelectorListener listener = new LeaderSelectorListenerAdapter() {
            public void takeLeadership(CuratorFramework client) throws InterruptedException {
                LOG.info("被提升为主节点！");
                try {
                    Thread.sleep(Long.MAX_VALUE);
                } catch (InterruptedException e) {
                    LOG.info("节点主动断开 or  主动让出主节点身份？反正此处是预期的打断！不需要打印堆栈");
                } finally {
                    LOG.info("主节点降级为普通节点！");
                }
            }
        };
        leaderElection.leaderSelector = new LeaderSelector(ZkConnection.client, ZkPathManager.getMyNodeBasePath(), listener);
        leaderElection.leaderSelector.autoRequeue(); //not required, but this is behavior that you will probably expect
        leaderElection.leaderSelector.start();
        singleton = leaderElection;
        LOG.info("ZkLeaderElection启动完毕.");
    }
}
 

@Override
public synchronized void unregister(final String roleName) {
    registeredRoles.remove(roleName);

    final LeaderRole leaderRole = leaderRoles.remove(roleName);
    if (leaderRole == null) {
        logger.info("Cannot unregister Leader Election Role '{}' becuase that role is not registered", roleName);
        return;
    }

    final LeaderSelector leaderSelector = leaderRole.getLeaderSelector();
    if (leaderSelector == null) {
        logger.info("Cannot unregister Leader Election Role '{}' becuase that role is not registered", roleName);
        return;
    }

    leaderSelector.close();
    logger.info("This node is no longer registered to be elected as the Leader for Role '{}'", roleName);
}
 

@Override
public synchronized void stop() {
    stopped = true;

    for (final Map.Entry<String, LeaderRole> entry : leaderRoles.entrySet()) {
        final LeaderRole role = entry.getValue();
        final LeaderSelector selector = role.getLeaderSelector();

        try {
            selector.close();
        } catch (final Exception e) {
            logger.warn("Failed to close Leader Selector for {}", entry.getKey(), e);
        }
    }

    leaderRoles.clear();

    if (curatorClient != null) {
        curatorClient.close();
        curatorClient = null;
    }

    logger.info("{} stopped and closed", this);
}
 

CuratorLeaderSelector(CuratorFramework client, String path, String name, JobEngineConfig jobEngineConfig) {
    this.name = name;
    this.leaderSelector = new LeaderSelector(client, path, this);
    this.leaderSelector.setId(name);
    this.leaderSelector.autoRequeue();
    this.jobEngineConfig = jobEngineConfig;
    this.defaultScheduler = DefaultScheduler.getInstance();
}
 

public static void election(final CountDownLatch cdl) {
    final CuratorFramework client = ZkUtils.getCuratorClient();
    final LeaderSelector selector = new LeaderSelector(client, Constants.MASTER_PATH, new LeaderSelectorListenerAdapter() {
        @Override
        public void takeLeadership(CuratorFramework curatorFramework) throws Exception {
            SWITCH_LOGGER.info("take master leadership");

            long seekTimestamp = MetaService.getSeekTimestamp();
            long zkSeekTimestamp = MetaService.getZkSeekTimestamp();
            final long sleepMs = 200;
            long sleepCount = 0;
            // 如果zk上的数据丢失了, 则zkSeekTimestamp为0, 此时chronos则被block住
            while (seekTimestamp < zkSeekTimestamp && zkSeekTimestamp > 0) {
                SWITCH_LOGGER.info("sleep {}ms to wait seekTimestamp:{} to catch up with zkSeekTimestamp:{}",
                        sleepMs, seekTimestamp, zkSeekTimestamp);
                TimeUnit.MILLISECONDS.sleep(sleepMs);
                seekTimestamp = MetaService.getSeekTimestamp();
                zkSeekTimestamp = MetaService.getZkSeekTimestamp();
                sleepCount++;
            }

            state = ServerState.MASTERING;
            SWITCH_LOGGER.info("change server state to {}, totalSleepMs:{}ms", state, sleepCount * sleepMs);
            cdl.await();
            state = ServerState.BACKUPING;
            SWITCH_LOGGER.info("release master leadership");
        }
    });
    selector.autoRequeue();
    selector.start();
}
 

/**
 * 执行选主
 */
private void electionLeader(){
    cfClient = ZKUtil.getClient(StreamContant.HDFS_HADOOP_ZOOKEEPER);
    if(cfClient == null){
        LOGGER.error("LeaderSelecter electionLeader failed so cfClient is null, HDFS_HADOOP_ZOOKEEPER=" + StreamContant.HDFS_HADOOP_ZOOKEEPER);
        return ;
    }
    leaderSelector = new LeaderSelector(cfClient, StreamContant.ZOOKEEPER_LEADER_DIR, this);
    leaderSelector.autoRequeue();
    leaderSelector.start();
}
 

public MasterSelector(String name, CuratorFramework client, String path) {
    this.name=name;
    //leaderSelector 多个客户端监听同一个节点
    this.leaderSelector=new LeaderSelector(client, path, this);
    //保证在此实例释放领导权之后还可能获得领导权
    leaderSelector.autoRequeue();
    //启动
    leaderSelector.start();
}
 

/**
 * Monitor to manage pravega host addition and removal in the cluster.
 *
 * @param hostStore             The store to read and write the host container mapping data.
 * @param client                The curator client for coordination.
 * @param balancer              The host to segment container balancer implementation.
 * @param minRebalanceInterval  The minimum interval between any two rebalance operations in seconds.
 *                              0 indicates there can be no waits between retries.
 */
public SegmentContainerMonitor(HostControllerStore hostStore, CuratorFramework client, ContainerBalancer balancer,
        int minRebalanceInterval) {
    Preconditions.checkNotNull(hostStore, "hostStore");
    Preconditions.checkNotNull(client, "client");
    Preconditions.checkNotNull(balancer, "balancer");

    leaderZKPath = ZKPaths.makePath("cluster", "faulthandlerleader");

    segmentMonitorLeader = new SegmentMonitorLeader(hostStore, balancer, minRebalanceInterval);
    leaderSelector = new LeaderSelector(client, leaderZKPath, segmentMonitorLeader);

    //Listen for any zookeeper connectivity error and relinquish leadership.
    client.getConnectionStateListenable().addListener(
            (curatorClient, newState) -> {
                switch (newState) {
                    case LOST:
                        log.warn("Connection to zookeeper lost, attempting to interrrupt the leader thread");
                        leaderSelector.interruptLeadership();
                        break;
                    case SUSPENDED:
                        if (leaderSelector.hasLeadership()) {
                            log.info("Zookeeper session suspended, pausing the segment monitor");
                            segmentMonitorLeader.suspend();
                        }
                        break;
                    case RECONNECTED:
                        if (leaderSelector.hasLeadership()) {
                            log.info("Zookeeper session reconnected, resume the segment monitor");
                            segmentMonitorLeader.resume();
                        }
                        break;
                    //$CASES-OMITTED$
                    default:
                        log.debug("Connection state to zookeeper updated: " + newState.toString());
                }
            }
    );
}
 

public ReplicaSetLeaderSelector(CuratorFramework client, Node currNode, int replicaSetID) {
    this.node = currNode;
    this.replicaSetID = replicaSetID;
    String path = StreamingUtils.REPLICASETS_LEADER_ELECT + "/" + replicaSetID;
    leaderSelector = new LeaderSelector(client, path, this);
    leaderSelector.autoRequeue();
    leaderChangeListeners = Lists.newArrayList();
}
 

public ClientSelector(String name,CuratorFramework client, String path) {
    this.name=name;
    //leaderSelector 多个客户端监听同一个节点
    this.leaderSelector=new LeaderSelector(client, path, this);
    //保证在此实例释放领导权之后还可能获得领导权
    leaderSelector.autoRequeue();
    //启动
    leaderSelector.start();
}
 

public void afterSingletonsInstantiated() {
	String basePath = String.format("%s/%s", this.workDirectory, this.getApplication());
	try {
		this.createPersistentPathIfNecessary(basePath);
	} catch (Exception ex) {
		throw new IllegalStateException(ex);
	}

	String masterPath = String.format("%s/master", basePath);
	this.leadSelector = new LeaderSelector(this.curatorFramework, masterPath, this);
	this.leadSelector.autoRequeue();
	this.leadSelector.start();
}
 

public ExampleClient(CuratorFramework client, String path, String name)
{
    this.name = name;

    // create a leader selector using the given path for management
    // all participants in a given leader selection must use the same path
    // ExampleClient here is also a LeaderSelectorListener but this isn't required
    leaderSelector = new LeaderSelector(client, path, this);

    // for most cases you will want your instance to requeue when it relinquishes leadership
    leaderSelector.autoRequeue();
}
 

private void leaderElection() {
    String ensemble = ZKConfig.getZKQuorumServersString(conf);
    CuratorFramework client = CuratorFrameworkFactory.newClient(ensemble, new ExponentialBackoffRetry(1000, 3));

    client.start();

    String leaderElectionPath = HConfiguration.getConfiguration().getSpliceRootPath()
            + HBaseConfiguration.OLAP_SERVER_PATH + HBaseConfiguration.OLAP_SERVER_LEADER_ELECTION_PATH
            + "/" + queueName;

    LeaderSelector leaderSelector = new LeaderSelector(client, leaderElectionPath, this);
    LOG.info("Starting leader election for OlapServer-"+queueName);
    leaderSelector.start();
}
 

public ReplicaSetLeaderSelector(CuratorFramework client, Node currNode, int replicaSetID) {
    this.node = currNode;
    this.replicaSetID = replicaSetID;
    String path = StreamingUtils.REPLICASETS_LEADER_ELECT + "/" + replicaSetID;
    leaderSelector = new LeaderSelector(client, path, this);
    leaderSelector.autoRequeue();
    leaderChangeListeners = Lists.newArrayList();
}
 

public ZkLeaderSelector(String path,
                        String key,
                        ZKConfig zkConfig,
                        ServerConfig sc,
                        HttpConfig hc,
                        IWorkInitializer workIni) {
    this.workIni = workIni;

    this.client = CuratorFrameworkFactory.newClient(
            zkConfig.getServers(),
            new RetryNTimes(zkConfig.getRetryTimes(), zkConfig.getSleepMsBetweenRetries())
    );
    this.client.start();

    this.leaderSelector = new LeaderSelector(client, path, this);
    this.leaderSelector.autoRequeue();

    this.serverConf = sc;
    this.httpConf = hc;
    this.path = path;
    this.key = key;
    this.host = sc.getHost();

    this.zkConf = zkConfig;

    this.binlogInfoPath = path + ConstUtils.ZK_DYNAMIC_PATH;
    this.counterPath = path + ConstUtils.ZK_COUNTER_PATH;
    this.terminalPath = path + ConstUtils.ZK_TERMINAL_PATH;
    this.candidatePath = path + ConstUtils.ZK_CANDIDATE_PATH;
    this.leaderPath = path + ConstUtils.ZK_LEADER_PATH;
    this.errorPath = path + ConstUtils.ZK_ERROR_PATH;
    this.alarmPath = path + ConstUtils.ZK_ALARM_PATH;
}
 

/**
 * 放弃leader 表明必须得停止dump
 * <p>
 * 停止dump 由外部调用 不是在这里调用 这里只是去除悬挂引用
 * <p>
 * 但是不关闭leader selector
 */
public void abandonLeaderShip() {
    LogUtils.debug.debug("abandonLeaderShip");
    LeaderSelector leaderSelector = this.leaderSelector;

    if (leaderSelector != null) {
        leaderSelector.interruptLeadership();
    }
    this.work = null;
    this.metaInfo = null;
}
 

public static void election(final CountDownLatch cdl) {
    final CuratorFramework client = ZkUtils.getCuratorClient();
    final LeaderSelector selector = new LeaderSelector(client, Constants.MASTER_PATH, new LeaderSelectorListenerAdapter() {
        @Override
        public void takeLeadership(CuratorFramework curatorFramework) throws Exception {
            SWITCH_LOGGER.info("take master leadership");

            long seekTimestamp = MetaService.getSeekTimestamp();
            long zkSeekTimestamp = MetaService.getZkSeekTimestamp();
            final long sleepMs = 200;
            long sleepCount = 0;
            // 如果zk上的数据丢失了, 则zkSeekTimestamp为0, 此时chronos则被block住
            while (seekTimestamp < zkSeekTimestamp && zkSeekTimestamp > 0) {
                SWITCH_LOGGER.info("sleep {}ms to wait seekTimestamp:{} to catch up with zkSeekTimestamp:{}",
                        sleepMs, seekTimestamp, zkSeekTimestamp);
                TimeUnit.MILLISECONDS.sleep(sleepMs);
                seekTimestamp = MetaService.getSeekTimestamp();
                zkSeekTimestamp = MetaService.getZkSeekTimestamp();
                sleepCount++;
            }

            state = ServerState.MASTERING;
            SWITCH_LOGGER.info("change server state to {}, totalSleepMs:{}ms", state, sleepCount * sleepMs);
            cdl.await();
            state = ServerState.BACKUPING;
            SWITCH_LOGGER.info("release master leadership");
        }
    });
    selector.autoRequeue();
    selector.start();
}
 

public ExampleClient(CuratorFramework client, String path, String name)
{
    this.name = name;

    // create a leader selector using the given path for management
    // all participants in a given leader selection must use the same path
    // ExampleClient here is also a LeaderSelectorListener but this isn't required
    leaderSelector = new LeaderSelector(client, path, this);

    // for most cases you will want your instance to requeue when it relinquishes leadership
    leaderSelector.autoRequeue();
}
 

CuratorLeaderSelector(CuratorFramework client, String path, String name, JobEngineConfig jobEngineConfig) {
    this.name = name;
    this.leaderSelector = new LeaderSelector(client, path, this);
    this.leaderSelector.setId(name);
    this.leaderSelector.autoRequeue();
    this.jobEngineConfig = jobEngineConfig;
    this.defaultScheduler = DefaultScheduler.getInstance();
}
 

/**
 * 如果参与了选举，那么退出主节点选举
 *
 * @deprecated curator的选举算法有问题，在最后一个唯一节点，同时也是主节点退出选举时，它抛出java.lang.InterruptedException。
 * 所以请直接依赖zk断开连接的方式退出节点选举，而不是调用本方法来退出选举
 */
public static void stop() {
    synchronized (lock) {
        if (singleton == null) return;
        LeaderSelector leaderSelector = singleton.leaderSelector;
        if (leaderSelector == null) {
            return;
        }
        LOG.info("节点退出zk选举");
        leaderSelector.close();
        singleton = null;
        LOG.info("退出选举 完毕");
    }
}
 

public ExampleClient(CuratorFramework client, String path, String name) {
	this.name = name;
	leaderSelector = new LeaderSelector(client, path, this);
	leaderSelector.autoRequeue();
}
 

public LeaderSelector getLeaderSelector() {
    return leaderSelector;
}
 

public LeaderRole(final LeaderSelector leaderSelector, final ElectionListener electionListener, final boolean participant) {
    this.leaderSelector = leaderSelector;
    this.electionListener = electionListener;
    this.participant = participant;
}
 

public LeaderSelectorClient(SchedulerDriver schedulerDriver) {
    leaderSelector = new LeaderSelector(schedulerDriver.getCuratorUtils().getClient(), ZKLOCKS + HTTP_SEPERATOR + MESOS_FRAMEWORK_TAG, this);
    leaderSelector.autoRequeue();
    this.schedulerDriver = schedulerDriver;

}
 

public LeaderSelector getLeaderSelector() {
    return leaderSelector;
}
 

@VisibleForTesting
LeaderSelector getLeaderSelector()
{
    return leaderSelector;
}